(1) Field of the Invention
This invention relates to electronic manual input devices, in particular relates to computer keyboards.
(2) Description of the Related Art
With the miniaturization of digital electronics and their increasing functionality, computers are getting smaller and smaller. Similarly, small electronic devices become capable of performing more and more functions. The handheld computers, such as Palm Pilot, Handspring, Pocket PCs are not only capable of being Personal Digital Assistants (PDA), which keep contact information, To-Do lists, Calendar and short memos, they are now having enough computing power and memories to be bona fide personal computers. Each of them is small enough to fit in a man""s shirt pocket or one""s hand. To maintain the compact size, most handheld computers do away with traditional keyboards. The main input devices for most handheld computers are styluses. The styluses are fine if one only need to input a person""s phone number or similar very minimum data entry. It becomes awkward, slow and painful when the data entry requirement is slightly more demanding, such as entering a long address, taking a note of an telephone call or To-Do item or taking note for a meeting or a lecture. Their input speeds are greatly reduced comparing to ten-finger touching typing using a regular keyboard. Using a stylus is almost equivalent to one-finger typing. Some of PDAs allow a combination of point and click typing and pen-based scribing. Some claim the combined clicking/scribing speeds up to 40 WPM, very close to regular keyboard typing, e.g. Silverscreen, a software-keyboard available for Palm PDA.
Similarly, other electronic gadgets, such as cellular phones, are small and have fairly large memories and many functionalities. But many of them only have numeral keys. To enter characters into the memory, one has to use numerical coding, i.e. presses a number key several times to enter one character or number. For example, on a Nokia 3390 cellular phone, to enter a letter xe2x80x9caxe2x80x9d, one needs to press 2, i.e. press number key 2 once and pause before pressing other keys. To enter a letter xe2x80x9coxe2x80x9d, one has to press 666, i.e. press number key 6 three times because xe2x80x9coxe2x80x9d is the third letter on key 6. To get a number 6, one has to press 6666, i.e. press number key 6 for four times, because 6 is the fourth symbol on key 6. It is very cumbersome.
The manual input device becomes increasingly the component that resists being miniaturized. A Go-type keyboard is a step forward in relieving the manual input device problem for handheld computers. But the Go-type keyboard is significantly larger than the Palm handheld computer and keys on the keyboard are significantly smaller when in use than the traditional keyboard. The Palm folding keyboard is smaller. A Palm folding keyboard is small enough to fit in a big pocket when not in use. It is only a little bit longer and wider than a Palm(trademark) computer and about twice as thick as a Palm(trademark). When the keyboard is extended and ready to use, it has a keyboard the size of a normal desktop computer keyboard. The keys on the keyboard are normal size and the travel distance of keys when depressed is about the same as the keys on a notebook computer keyboard or about half of that as the keys on a desktop computer keyboard. A Palm folding keyboard is significantly smaller when folded than a full-size desktop computer keyboard, i.e. about xc2xc of a regular keyboard. But it is still too big to carry with a Palm simultaneously in a shirt pocket. A Palm folding keyboard is significantly more expensive than a regular desktop keyboard, about $100 for a Palm folding keyboard versus $15 or less for a regular desktop keyboard.
Most of the desktop keyboards, Palm folding keyboards or even the miniaturized keyboards have plastic keycaps. Under those keycaps, there are springs or similar resilient material, which will spring back to it original position when not pressed. When a user hits a key, the spring will be depressed, a rod underneath the keycap or other mechanic component will hit a plastic electrical switch, and the switch closes an electric circuit. When the finger releases the keycap, the string under the keycap returns to neutral position, so the plastic electric switch opens again. The open or close of such an electric switch will generate a signal, which may or may not be forwarded to an input driver. Eventually, the signal will be forwarded to a dedicated microprocessor or a Central Processing Unit (CPU) and be processed as the corresponding keystroke represented by the keycap on the keyboard. The mechanical movement of the keycaps on the keyboard is transformed into electrical signal and processed by CPU as an input keystroke. The sizes of those keycaps on a keyboard are mostly determined by the sizes of human fingers. To make the keycaps fit the fingers, the size of the keycaps cannot be too small, otherwise, the finger will not be able move and hit the correct keys all the time. Smaller keycaps, as in the Go-type keyboard are not as comfortable or accurate as those full-size keycaps as in the desktop keyboard or Palm folding keyboard. If the keycaps are too big, then the fingers have to travel more to hit a particular keycap. That increases chances of hitting a wrong, adjacent keycap. That also may increase hand fatigue. Some keyboard manufacturers have recognized such problems and have developed smaller keyboards for persons with smaller hands and fingers, such as children.
Touch screens are used increasingly common. On a screen, part of the screen may be shown as a simulated desktop keyboard. When a human finger touches a location inside a simulated key, the touch screen generates a signal representing the coordinates of the hit location. A program, such as keyboard driver, interprets such a signal as a keystroke, as if one typed the same key on a regular keyboard. Those touch screen keyboards are usually in vertical planes, as they are usually the bottom portions of vertical displaying screens. The touch screen eliminates the need of additional keyboards, makes the system of compact and integrated with fewer mechanical accessories. A touch screen is also easier to clean or sanitize, where public health is of concern. But touch screens are intended for inputting minimum amount of information, such as selecting an item from a list or inputting a person""s name, rather than heavy-duty keyboards, such as for taking notes or writing office memoranda. There are touch screens displaying on near horizontal plans such in some instrument panels in control rooms in many manufacturing plants. There, simulated keyboards on a horizontal plane may be used occasionally as if they are desktop keyboards.
The present invention takes advantage of certain features of manual input devices, such as a typical keyboard, and minimizes the sizes of them. The keyless keyboard in the present invention does not use any keycaps. The present invention may have a film of membrane switches with printed circuits or touch screens. The film may have a plurality of areas representing keys. The film may be folded many times to reduce the size. A connector connects the keyboard to electronic devices, such as PDAs, cellular phones or desktop computers.